Screen



March 2,1926. 1,575,457

. A. H. STEBBINS SCREEN Filed March 6, 1925 A TTOR/VEY .closed casing.

Patented Mar. 2, 1926.

UNITED STATES PATENT Fries,

ALBERT H. STEYBBINS, OFLQS ANGELES, CALIFORNIA.

scimniv,

Application filed March 6, 1925. Serial N0. 13,442.

To all whom it may concern:

. Be it known that I, ALBERT H. STnnnINs, a citizen of the United States, residing at Los Angeles, in the county of LosAngeles and State of California have invented an Improvement in Screens, of which the following description, in connection with the accompanying drawings, is a specification,

like characters on the drawings representing other openings in the casing, which is objectionable.

The present invention therefore relates to means for removing the dust laden air from the screen casing, and the construction is such that it serves also to classify the lighter materials picked up by the air.

The novel features of the invention and combination of parts will be hereinafter described in connection with the accompanying drawings, which illustrate one good, practical form thereof. 7 i

In the drawings Fig. 1 is a side elevation with parts in section of a vibratory screen embodying the present invention.

Fig. 2 is a sectional view taken on the line 22 of Fig. 1; and

Fig. 3 is an enlarged sectional View of a portion of the operating shaft and one of the operating sheaves.

The present invention may be employed with any type of screen that is provided with a closed'casing, and inthe present case is shown as applied to a vibratory screen of the inclined type.

The screen casing may be variously con structed and as shown is provided with the side walls 10 secured to the cover 11 and floor 12, and the casing may be strengthened by longitudinally extending beams 13 se cured to the side walls. The screen casing may be' provided with one or more screening surfaces and is shown as having an upper screening surface and a lower screening surface 15 secured to the side walls 10. The materials to be treated are delivered to screen casing.

the upper screen by one or more hoppers 16.

The larger particles that fail to pass through the upper screen are discharged through the chute 17, while the particles that do not pass through the lower screen are discharged throu 'h the chute 18, and the fine particles that fall upon the floor 12 are discharged through the chute 19. A p

The screen shown is supported to slope in the direction of its length, and is mounted upon a frame formed of side beams 20,0 11

nected by transverse braces 21.v The lower end of this frame is pivotally secured to base timbers 22 at 23 and theupperend of the.

frame is supported by uprights 24Esecu1 ed to the timbers 22 and having the slotted braces 25 adjustablysecured to the uprights by bolts 26.

Various means may be provided'for supporting the screen for vibratory movement and for vibrating the same, and in the construction shown the screen casing is yieldingly mounted upon the supporting frame by coiled springs 27 seatedupon the frame and the upper ends ofwhich restagainst the transversely extending braces 28 of the The means shown for imparting a vibratory movement to the screen casing consists of cables 29 at each side of the casing and one end of each cable is secured to the casing byaclamp 30, while the opposite end of each cable is fastened to the frame at 31. The intermediate portion of each cable passes around a grooved sheave 32 operated by eccentrics 33 upon the transversely extending shaft 34 that is rotatablymounted in bearings 35. The eccentrics 33 are rotatably mounted Within the sheaves 82,1 and rollers or other anti-friction tries and sheaves. that as the shaft 34 isrotated it moves the sheaves S2 to and from the cable tightening position, thus pulling the screen casing slightly in an upward direction and then releasing it to move downwardly under the force of gravity.

The mechanism so far described may be of well known'or any preferred construction and is illustrated and described to make clear theapplication of the present invention to a closed screen casing. The means of the present invention for removin dust laden air from the casing will now edescribed, and to this end a eondultis provided within the screen casing below the bearingsBG are provided between the eccen- The arrangement is such screening. surface 1-5 and has an open end through which air is drawn from the casing into the conduit. The conduit is conveniently formed by providing a partition 37 within the casing which extends downward from the upper end of the casing a substan-- tial distance between the floor 12 and screening surface 15. Air is exhausted from the chamber 38 formed between. the partition and floor by a pipe 39 which may be connected. to a suction fan. The chamber 38 is made relatively large and of substantial length so that the heavier particles carried. upwardly by the air'will have an opportunity to settle therein and slide down the floor of this chamber. I

It is desirable to provide a door within the chamber 38 to control the passage of air ther'ethrough, and in the construction shown this is accomplished by providing'the swingingtrap 4O pivotally supported at il and arranged to restrict the air passage, the arrangement being such that the trap is free to swing upwardly sufficient to allow the particles that are carried upwardly by the air and lodge back of the trapito escape. The restricted air passage formed by the trap 40 may be varied in size by adjusting the door 42 pivotally mounted at 41 and which is urged upwardly by springs 43.

.Thedoor' 42 is held open the desired amount y bolts 44' having adjustable nuts upon their outer endsr It may be desirable to admit air into the screen casing. at one or more points and to this. end. the air inlet openings 4'5 are pr0- vided the size. off which may be adjusted by adjusting. the bolts 46.

From the foregoingit will be seen that the dust laden airwithin the screen casing will travel in the directionsindicatedj by the arrows toward the entrance to the chamber 37 and then. up. this chamber. The restricted passage formed; in this chamber by the trap 40 servesto retardthe flow of air therein; this. gives the. heavier particles a chance to settle therein andv slide down the flo0r12 to the exit 19. The eccentric shaft 84 may be driven from an the belt L8; 7

What is. claimed is: V

1.. In a. screen, in combination, a closed casing supported at an inclination I11! thedi rection. of its l.ength,a partition in the casing below the screening surfaceand extending from the upper end of the casing lengthwise thereof a. substantial distance to provide an air chamber below the'partition, and means for exhausting air fromv the upper end of said chamber to draw the dust laden air within. the casing upward through.- said chamber in opposition to the force of gravity to cause; the heavier particles car ried upwardly by the air to settle in the operating shaft 47 by chamber and slide downwardly therein.

2.111 a screen, in combination, a closed casing supported at an inclination in the direction of its length, a screening surface within the? casing, partition mounted in the casing below the screening surface and extending from the upper end of the casing lengthwise thereof a substantial distance to provide an air chamber below the partition, means at the upper end of the air chamber for exhausting air from said chamber to draw the dust laden air. with the casing upward through said chamber so that the heavier particles carried upwardly by the air may settle in the chamber, and an adjustable door to control the passage of air from said chamber;

3. In a screen, incombination, a closed casing supported at an inclination in the direction of its length, a screeningsurface within the casing, a' partition mounted in the casing below the screening surface and extending from the upper end of the casing lengthwise thereof a substantial distance-1n spaced relation. to the casing floor so that the materials that pass through the screening Surface fall upon the partition and are excluded thereby from'the' chamber formed betweenthe partition and floor, and means at the upper end of said chamber for' exhausting air from the chamber to d'ra'wf' the dust laden air within the easing into said chamber at the lower end, of the partition and upwardly within the chamber to promote settling of the heavier 1)ai't-icl'es'carried upwardly by" the. air.

4. In a screen, in combination, a closed casing supported; at an inclination in the direction of its length, a screening surface within the casing, an air conduit extendinglongr tudinally within the casing below the screening surfacev and open at its lower end, means for exhausting air from said conduit to draw the dust laden air within the casing upwardly through the conduit, and a trap duit extending longitudinally within the' casing below the screening surface and open at its lower end, and means for drawing air upwardly through said conduit to remove dust laden air from said casing so that the air is caused to travel a substantialdistance in an upward direction within the conduit and the heavier particles are afforded an opportunity'to settle in the conduit and slide downwardly therein.

61 In a screen, 1n combination, a closed casing supported at an inclination in the direction of its length, a screening surface Within the casing, a partition mounted in the casing below the screening surface and extending from the upper end of the casing downwardly therein a substantial distance to provide an air chamber below the partition, means at the upper end of the air chamber for exhausting air from said chamber to draw dust laden air into thelower portion of the casing and upwardly therein, and an inclined plate within said chamber for arresting the heavier particles carried upwardly therein by the air.

In testimony whereof, I have signed my name to this specification.

ALBERT H. STEBBINS. 

